I forgot to add a space between the inferior's package name and package version, I've attached a patch that fixes this.

On Fri, 21 Dec 2018 16:20:10 +0100, Ludovic Courtès <ludo@gnu.org> wrote:

> Hi,
> 
> <pkill9@runbox.com> skribis:
> 
> > From 0e86c0708f3aa0eb35a9fc3c9ef89dcb210bac3f Mon Sep 17 00:00:00 2001
> > From: Pkill -9 <pkill9@runbox.com>
> > Date: Wed, 19 Dec 2018 20:22:20 +0000
> > Subject: [PATCH] system: 'kernel->boot-label' now accepts inferior packages.
> >
> > * gnu/system.scm (kernel->boot-label): Get package name and version
> > using the functions for inferior packages if the kernel is an
> > inferior package. Return "GNU" if the kernel is not a package.
> 
> I adjusted the indentation and applied.  Thank you!
> 
> Ludo’.